simplifying credit card debt (BETA) from 2006

I've had a problem understanding credit cards since the first time I was offered one in college. The idea sounds great. You have access to almost infinite money. Furthermore you are told that you have to be in debt in order to have a good credit report later on when you might want to buy a car or house. A major problem in the US now is the inability for many people to pay off their credit card debt. I looked online for some way to better understand how this all works, and wrote this simple little system to have an 'aha' moment. I hope it is useful to you.
(Note that this system assumes that there is no annual fee, and that a minimum of $10 must be paid per month if the Minimum Monthly Payment is less than $10).